The present invention relates to a new and improved strap dispenser, in which the strap in coils may be removed at high speeds, either manually or automatically with minimal shock load to the dispenser and without strap overrun thereby eliminating the possibility of snarling of the unwound strap material.
It has been a common practice in the past to dispense the strapping tangentially from the strapping coil. For all such dispensers, the mass inertia of the strap coils must be overcome before the appropriate speed necessary for the dispensing process is reached. This mass and inertia was overcome primarily by the use of very large motors and some form of accumulator mechanism which allowed for the immediate supply of strapping to the strapping machine during the time that the motor acts on the reel to overcome the mass and inertia thereof. An example of an accumulator means appears in U.S. Pat. No. 4,153,499 granted to James R. Annis on May 8, 1979 and assigned to the assignee of the present invention.
Another problem associated with the prior art strap dispensers is that once this static inertia is overcome, there is a certain amount of rotational inertia which will continue to supply strapping even after the motor is deactivated. Various devices were used in the prior art strap dispensers to overcome the rotational inertia in order to prevent unneeded strapping from overrunning the machine resulting in strapping lying loose between the coil and the feed mechanism of the strapping machine which could result in tangling and snagging.
An additional problem has been created with the use of thinner non-metallic strapping since this thinner non-metallic strapping is difficult to thread in the accumulator mechanism.
There has been a need for a dispenser mechanism which will respond in accordance with the demand for strap material and which can stop and start easily in proportion to the demand for and the supply of the material with very simple operation. The present invention has solved the foregoing problems in a unique method. Strapping is removed non-tangentially from the reel of strapping. Such non-tangential removal of the strapping does not require the reel of strapping to be rotated in order to allow the strapping to reach the speed the demand requires. On the other hand, non-tangential removal of the strapping alone will create strapping that is twisted and will eventually snarl. To overcome this problem this new strap dispenser eliminates the twisting of the strapping by recording the circumferential movement of the strap about the circumference of the reel as the strapping is being removed and thereafter actuating a motor which will rotate the reel of strapping in the opposite direction an equivalent amount to eliminate the twist.